Light powered switch



March 14, 1961 J. HARRIS LIGHT POWERED SWITCH Filed March 5, 1958 INVENTOR.

JACK HARRIS ATTORNEYS.

LIGHT POWERED SWITCH Jack Harris, Tenafly, N.J., assignor to Anton Electronic Laboratories, 1110., Brooklyn, N.Y., a corporation of New York Filed Mar. 5, 1958, Ser. No. 719,295

7 Claims. (Cl. 317-129) This application relates to a light powered switch and in particular to a switch utilizing a photocell to control the operation of a relay circuit.

The numerous uses for switches that respond to variable light sources are too well known to require an extended discussion here. Although many devices have been developed most are unsuited to the highly mechanized and miniaturized industrial uses of today. in general, a common fault in devices of this type is that they require an external voltage source or an amplifier coupled to the photoelectric cell to increase its power output so as to overcome the external resistance of the relay circuit. This is because the relay circuits have been made relatively large and thus require a sufficiently high armature torque to operate. Such use of additional elements has caused these devices to be larger, more difiicult to use and relatively more expensive than is practicably desirable. further problem arises in magnetic control relays, in that it is necessary to provide large magnets forming a field of considerable strength. Correspondingly the related structure must also be of considerable size. Modern requirements call for the elimination of these unnecessary and encumbering elements and the provision of a simple, compact and inexpensive light sensitive switch.

It is therefore an object of this invention to provide a miniature light sensitive switch that does not require the use of any sensitivity increasing means such as an amplifier or external voltage source, and in particular a miniature device inwhich a relay circuit is directly operable by a photoelectric cell.

It is another object of this invention to provide a light sensitive switch that is formed into a single unit having relatively small and compact dimensions for a variety of uses and functions.

A further object of this invention is to provide a light sensitive switch in which the switching relay contains a magnet of relatively small dimension but high strength.

It is another object of this invention to provide a light 7 sensitive switch that may be used either as a single pole,

single throw or a single pole, double throw relay switch.

It is another object to provide a light sensitive switch made of simple and inexpensive parts, inexpensively constructed and capable of inexpensive operation.

Other and more detailed objects and advantages of this invention will be obvious from the following description and the attached drawings in which Figure 1 is an exploded assembly view of a device embodying this invention;

Figure 2 is a vertical cross-section view of the device of Figure l, in assembled form showing the details of the relay used in this embodiment;

Figure 3 is a top plan view of the device of Figures 1 and 2 showing the relay switch;

Figure 4 is an exploded assembly view of the photocell used in the device of Figures 1 to 3;

Figure 5 is a circuit diagram of the embodiment of this invention, and

atent 0 Figure 6 is a vertical cross-section view taken along lines 66 of Figure 2.

Referring now specifically to the drawings, the embodiment of the invention there disclosed comprises a cylindrical housing 10, illustratively one and one-half inches in diameter and approximately one inch in height, having a cover 11 made of molded plastic or similar nonconductive material, within which are mounted a photoelectric cell unit 12 and a galvanometer meter movement relay switch 13. The cover 11 has a circular opening 14 in which is secured a transparent window 15 of glass or clear plastic permitting light to strike directly on the photocell 12.

The photocell as seen in exploded form in Figure 4 for convenience comprises a Phosphor bronze electrode 16, a soft steel filler or base plate 17 having a layer of selenium 18 deposited thereon and over which is coated a transparent film of gold or silver 19. The coated selenium forms a negative electrode to which is attached a tin or cadmium terminal ring 20. A corrugated bronze ring 21 is utilized to center and retain the coated base plate 17 and Phosphor bronze electrode 16 on a plastic ring 22 to which the Phosphor bronze electrode 16 is riveted or fastened by other suitable means as at points 23 so as to form a single compact unit. This single photocell unit may have a thickness of only a fraction of an inch and a diameter of approximately one inch. The corrugated bronze ring 21 is provided with a tab A which serves as an external contact terminal for the negative selenium electrode 18. Similarly the Phosphor bronze electrode 16 has a tab B serving as an external terminal.

Photocell 12 is of the photovoltaic barrier-layer type producing for its size a relatively high voltage output in relation to the amount of incident light. A cell of the size used in this embodiment has been found to have an open circuit reading of approximately 1 volt per 10 foot candles. However, other cells of greater or lesser size and/ or power production may be employed.

The galvanometer meter movement relay 13 as seen in Figures 2 and 6 is mounted within a pair of cross U-shaped magnetic members 24 and 25, which may be formed integrally as a single cruciform piece with bentup ends. A cylindrical permanent magnet 26 made of Alnico V or similar material is suitably cemented as with an epoxy resin or soft solder on a brass or other non-magnetic base 27 in the center of the crossed U- shaped members 24 and 25. A metal terminal post or stud 28 is staked or otherwise secured through the U- shaped members 24 and 25 into the brass base 27 and is fastened to the housing 10 by cooperatively acting nuts 29 and 30. Pivotally mounted about the permanent magnet 26 is a rectangular coil armature 31 formed of a highly conductive wire 32 such as copper or similar material wound about a bobbin 33. Conically tipped pivot shafts 34 and 35 are respectively insulatingly cemented to the bobbin 33 and are pivotally mounted in nonconductive jewel screw bearings 36 and 37 that are se cured to the end walls of the U-shaped member 24 by lock nuts 38 and 39 respectively. The jewel screw bearings 36 and 37 on the pivot shafts 34 and 35 are readily adjustable so that the coil 31 may freely pivot. Spiral metal hair springs 42 and '43 are respectively attached at their inner ends to pivot shafts 34 and 35 and at their outer ends to L-shaped rigid metal regulator arms 44 and 45 respectively. The regulator arms 44 and 45 are insulated from the lock nuts 38 and 39 by insulating washers 40 and 41, and extend around the side of the bracket member 24 so as not to be in contact with it. Spring washers 46 and 47 are mounted in cooperation with the lock nuts 38 and 39 respectively so as to retain the regulator arms in fixed position while permitting them to be manually adjusted without disturbing the adjustment of the jewel screw bearings 36 and 37. By use of the regulator arms 44 and 45 the rest position and operation of the coil 31 with respect to the permanent magnet 26 may be determined and adjusted as desired. Hair spring lugs 48 and 49 respectively secured to one end of the coil 32 and to the respective spiral hair springs 42 and 43, make electrical connection therebetween. Conductive Wire lead 50 from regulator arm 44 and lead 51 from regulator arm 45 connect to terminals A and B respectively so that photocell 12 may deliver energy directly to the coil armature 31. Staked to the top of frame members 24 and 25 by ears 52 is a flat non-conductive plate 53 on which a stationary contact spring 54 and stop 55 are mounted. The spring 54 has a portion 56 at its end which extends through plate 53 to make contact to frame member 24. A balance cross 57 having an arm 58 which extends upwardly through the cover plate 53 is mounted on pivot shaft 34 so as to pivot between the contact spring 54 and the stop 55 as the coil 31 is caused to pivot about the magnet 26. It is obvious that stop 55 may be easily converted into a second contact by merely providing means for connecting at its end a supplemental terminal. In this way a single pole, double throw switch may be provided as desired.

Terminal post 28 which is electrically connected to frame members 24 and 25 is accompanied by a second terminal post 60 mounted on housing 10. Conductive wire lead 61 connects terminal post 60 to terminal A of the corrugated bronze ring 21.

The cylindrical magnet 26 is formed so that its poles are on either side of it, in a horizontal diametral plane passing through the longitudinal axis of the cylinder, and provides for a magnetic circuit flowing from one pole through the U-shaped member 25 t the other pole. The strongest field of flux is readily noted to be within the area between the poles of the magnet 26 and the upper arms of the member 25, in which the coil 31 lies.

Light striking the photocell 12 will create a potential difference between the gold or silver coated selenium electrode 18 and the Phosphor bronze electrode 16 which are respectively positively and negatively charged. A flow of current will then be caused to flow from terminal B of the Phosphor bronze back plate 16 through lead 51, regulator arm 45, spring 43, lug 49 into coil 31; from coil 31 through lug 423, spring 42, regulator 44 and lead 50 to terminal A of the selenium electrode 18.

The flow of current through coil 31, which is in the field of flux of magnet 26, produces an armature torque sufiicient to cause coil 31 to pivot about the magnet 26, and cause balance cross 57 to engage stationary contact 54 at terminal C. Upon engagement of the contacts 57 and 54 a relay circuit is complete between external contacts 28 and 60. This relay circuit may be traced from terminal 28 through frame member 24, contact 54, balance cross 57, pivot shaft 34, hair spring 42, regulator arm 44 and lead 50 and subsequently to terminal 60.

Thus it is readily observable that the device shown herein provides an extremely simple uncomplicated light sensitive switch of miniature size. The use of the structural elements as members individually and simultaneously of the various magnetic and electrical circuits conserves space and provides economy in construction. The provision of a cylindrical magnet within the U-shaped housing provides a field of flux of relatively great strength which is space saving and economical.

Other modifications and changes may be readily made without departure from the concept of this invention, and it is therefore desired not to be limited by the disclosure set forth herein, which is illustrative only, but only by the claims as appended hereto.

What is claimed is:

l. A light powered switch comprising in combination,

a non-conductive housing having a bottom wall, first and second external terminals extending therefrom and a cover having a windowed aperture, a photocell mounted within said cover having a light sensitive face disposed within said cover aperture and a voltage output variable as a function of the light incident thereon, a galvanometric movement relay mounted within said housing comprising a U-shaped conductive frame mounted on said first external terminal having a non-conductive cover plate secured thereto and a non-conductive bearing mounted in each of its arms, a non-magnetic post secured to said first external terminal and extending within said frame, a permanent cylindrical magnet secured to said post, a rectangular coil having a pair of oppositely extending pivot shafts secured to the ends of said coil respectively and pivotally mounted within said bearings, said coil being adapted to pivot about said magnet, a spiral hair spring mounted about each of said shafts, each of which has its inner end attached to said shaft and its outer end insulatingly attached to said frame so as to retain said coil in rest position, a movable contact arm mounted on one of said shafts and extending through said non-conductive cover plate, a stationary contact mounted on said cover plate and connected to said frame, contact leads connecting said photocell to said coil shafts respectively, and contact leads connecting said second external terminal to said one pivot shaft having said movable contact mounted thereon whereby the voltage produced by said photocell causes a current to flow through said coil pivoting said coil about said magnet and causing said movable contact to engage said stationary contact so as to complete a circuit connection between said first and second external terminals.

2. A light powered switch comprising, in combination, a non-conductive cylindrical housing having a bottom wall, first and second external terminals extending therefrom and a cover having a windowed aperture, a photocell mounted within said cover having a light sensitive face disposed within said cover aperture and a voltage output variable as a function of the light incident thereon, a galvanometric movement relay mounted in said cylindrical housing comprising a conductive frame comprising a first and second U-shaped member crossed at their bases and mounted on said first external terminal, a non-magnetic post secured to said first external terminal and extending within said frame, a cylindrical permanent magnet secured to said post having its longitudinal axis parallel to the base of said U-shaped members, said magnet having its poles lying substantially in a diametral plane passing through the axis of said cylinder so as to provide a field of force substantially between said poles and the arms of said first U-shaped frame member, a rectangular coil electrically connected to said photocell and pivotally mounted between the arms of said second U-shaped member, said coil lying substantially within said field of force between said magnet and the arms of said first U-shaped member, said coil being adapted to pivot about said magnet when a current is caused to be applied thereto, a stationary contact electrically connected to said frame, and a movable contact controlled by said coil and electrically connected to said second external terminal whereby the voltage produced by said photocell causes a current to flow through said coil pivoting said coil about said magnet and causing said movable contact to engage said stationary contact so as to complete a circuit connection between said first and second external terminals.

3. A light powered switch comprising, in combination, a non-conductive housing having a bottom wall, first and second external terminals extending therefrom and a cover having a windowed aperture, a photocell mounted within said cover having a light sensitive face disposed within said cover aperture and a voltage output variable as a function of the light incident thereon, a galvanometric movement relay mounted in said cylindrical housing comprising a conductive frame comprising a first and second U-shaped member crossed at their bases and mounted on said first external terminal, said conductive frame having a non-conductive cover plate secured to the upper arms of said U-shaped members, a non-magnetic post secured to said first external terminal and extending within said frame, a cylindrical permanent magnet secured to said post having its longitudinal axis parallel to the base of said frame, said magnet having its poles lying substantially in a diametral plane passing through the axis of said cylinder so as to provide a field of force substantially between said poles and said firs-t U-shaped member, a non-conductive bearing mounted in each of the arms of said second U-shaped member, a rectangular coil mounted about said magnet having a pair of pivot shafts secured at opposite ends thereof and mounted respectively in each of said bearings, a pair of L-shaped conductive members, each having a first arm insulatingly mounted at its end to a respective arm of said second U-shaped member and having a second arm extending within said frame adjacent said respective pivot shafts, a spiral hair spring mounted about each of said pivot shafts, each of said hair springs having its inner end attached to a respective one of said shafts and its outer end connected to a respective one of said adjacent L-shaped member arms, means for electrically connecting said photocell to said coil comprising in part said respective L-shaped arms and spiral hair springs, a movable contact arm mounted on one of said pivot shafts and extending through said non-conductive cover plate, means for electrically connecting said movable contact to said second. external terminal comprising in part said pivot shaft, spiral hair spring and L-shaped arm adjacent said movable contact, a stationary contact mounted on said cover plate and electrically connected to said frame and said first external terminal whereby the voltage produced by said photocell causes a current to flow through said coil pivoting said coil about said magnet and causing said movable contact to engage said stationary contact so as to complete a circuit connection between said first and second external coils.

4. A light powered switch as claimed in claim 3 wherein said non-conductive bearings are provided with screw adjustment means for adjusting the pressure on said pivot shafts whereby the movement of said coil may be controlled as desired.

5. A light powered switch as claimed in claim 3 wherein said L-shaped arms are adjustably mounted on said frame so that the rest position of said coil may be varied as desired.

6. A light powered switch comprising, in combination, a non-conductive housing having a bottom wall, first and second external terminals extending therefrom and a cover having a windowed aperture, a photocell mounted within said cover having a light sensitive face disposed within said cover aperture and a voltage output variable as a function of the light incident thereon, a galvanometric movement relay mounted in said cylindrical housing comprising a conductive frame comprising a first and second vU-shaped member crossed at their bases and mounted on said first external terminal, said conductive frame having a non-conductive cover plate secured to the upper arms of said U-shaped members, a non-magnetic post secured to said first external terminal and extending within said frame, a cylindrical permanent magnet secured to said post having its longitudinal axis parallel to the base of said frame, said magnet having its poles lying substantially in a diametral plane passing through the axis of said cylinder so as to provide a field of force substantially between said poles and said first U-shaped member, a non-conductive bearing mounted in each of the arms of said second U-shaped member, a rectangular coil pivotal- 1y mounted about said magnet having a pair of pivot shafts secured at opposite ends thereof and mounted respectively in each of said bearings, a pair of L-shaped conductive members each having a first arm insulatingly mounted at its end to a respective arm of said second U-shaped member and having a second arm extending within said frame adjacent said respective pivot shafts, a spiral hair spring mounted about each of said pivot shafts, each of said hair springs having its inner end attached to a respective one of said shafts and its outer end connected to a respective one of said adjacent Lshaped member arms, means for electrically connecting said photocell to said coil comprising in part said respective L-shaped arms, and spinal hair springs, a movable contact arm mounted on one of said pivot shafts and extending through said non-conductive cover plate, means for electrically connecting said movable contact to said second external terminal comprising in part said pivot shaft,

spiral hair spring and L-shaped arm adjacent said movable contact, a first stationary contact mounted on said cover plate and electrically connected to said frame and said first external terminal, a second stationary contact mounted on said cover plate in juxtaposed position to said first contact and having means for making electrical connection therewith whereby the voltage produced by said photocell causes a current to flow through said coil pivoting said coil about said magnet and causing said movable contact to engage said first or second stationary contact alternately according to whether the light incident upon said photocell is above or below a predetermined level.

7. A light powered switch comprising in combination, a non-conductive housing having a bottom wall, first and second external terminals extending therefrom and a cover having a windowed aperture, a photo-cell mounted within said cover having a light sensitive face exposed within said cover aperture and a voltage output variable as the function of the light incident thereon, a galvanometric movement relay mounted within said housing comprising a conductive frame mounted on said first external terminal, a non-magnetic post secured to said first external terminal and extending within said frame, a permanent magnet secured to said post, a rectangular coil having a pair of oppositely extending pivot shafts secured to the ends of said coil and pivotall y and non-conductively mounted on and within said frame, said coil being adapted to pivot about said magnet, a spiral hair-spring mounted about one of said pivot shafts and having its inner end attached to said shaft and it outer end insulatingly attached to said frame so as to retain said coil in rest position, contact leads connecting said photo-cell to said coil shaft respectively, a stationary contact electrically connected to said frame, and a movable contact controlled by said coil and electrically connected to said second external terminal and adapted to make contact engagement with said stationary con-tact according to whether the light incident upon said photo-cell is above or below a predetermined level, whereby the voltage produced by said photocell causes -a current to flow through said coil pivoting said coil about said magnet and causing said movable contact to engage said stationary contact so as to complete a circuit connection between said first and second external terminals.

References Cited in the file of this patent UNITED STATES PATENTS 1,779,574 Wein Oct. 28, 1930 2,237,579 Ronning Apr. 8, 1941 2,286,036 Lamb June 9, 1942 2,331,475 Johnson Oct. 12, 1943 2,753,492 Jay July 3, 1956 

